Capacitors are typically connected between a voltage source and other devices. Referring to FIG. 1, a voltage source 10 is connected in parallel with a capacitor 11 and a device 14. The capacitor 11 may be a film capacitor that provides a filtering effect and may be used to reduce ripple current.
For example, the capacitor may be used between a voltage source such as a battery of a vehicle and a DC-DC converter. When the first time the DC-DC converter with the capacitor is connected to the battery surge currents may occur that can damage the capacitor. In vehicle applications, high surge voltage may occur which exclude the use of capacitors with low voltage surge capability.
While film capacitors have been used in higher surge voltage and current applications, they have very large size and much higher cost than other type of capacitors. In vehicle applications such as fuel cells and hybrids vehicles where size and cost are very important, film capacitors are not desirable.